1. Field of Invention
The present invention relates to a method for operating a semiconductor device. More particularly, the present invention relates to a method for operating a photosensitive device.
2. Description of Related Art
Nowadays, an image sensor is a device that converts an optical image to an electrical signal. It is a set of charge-coupled devices (CCD) or CMOS sensors such as active-pixel sensors.
In particular, CMOS image sensor (CIS) device is featured by lower operating voltage, lower power consumption and higher operating efficiency than that of CCD. Besides, CIS device can be produced in CMOS manufacturing process, so CIS device is widely applied in videophone, digital camera, mobile phone and aerospace industry.
Recently, as energy saving and environmental protection are becoming increasingly pressing issues, the countries and electronic society have launched a wide series of policies and set a lot of industry standard for power saving. Many companies are trying novel and effective approaches to meet this for power reduction. One of examples is to use the image sensor. Photo sensor (or photo detection device) is a quite critical embedded element for power-saving. For example, when the ambient light is bright, an integrated system (like a outdoor lighting system) can automatically cut down the power output to certain level by the assistance of the image sensor through detecting the incident lights.